Bio 1201 gregg Exam 2 (100% correct and graded A+)

transport proteins - are responsible for controlling passage across the membrane fluid mosaic model - The membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids fatty acid tails - nonpolar, hydrophobic fatty acid heads - hydrophilic, polar periphial proteins - bound to the surface of the membrane integral proteins - penetrate the hydrophobic core (ones that span the membrane are transmembrane protiens How do cells recognize each other? - by binding to molecules, often containing carbohydrates, on the extracellular surface of the plasma membrane Glycolipids - Membrane carbohydrates that are covalently bonded to lipids. Hypdrophobic - molecules such as hydrocarbons that can dissolve in the lipid bilayer and pass through the membrane rapidly Hydrophilic - molecules that don't cross the membrane easily (ions and polar molecules) transport proteins - allow passage of hydrophilic substances across the membrane carrier proteins - bind to molecules and change shape to shuttle them across the membrane passive transport - the diffusion of a substance across a membrane with no energy investmentDiffusuion - Spreading out of particles away from each other, from an area of high concentration to an area of low concentration. (move to where space is available) concentation gradient - substances diffuse from high concentration----> low concentration Osmosis - Diffusion of water through a selectively permeable membrane Isotonic - when the concentration of two solutions is the same (no net movement) Hypertonic - cell losses water and shrivils hypertonic - cell gains water and expands In a plant cell water moves in and out affecting the size of what? - central vacuole facilitated diffusion - the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins ion channels - channel proteins that transport ions gated channels - open or close in response to a stimulus active transport - requires energy (ATP) to move substances against their concentration gradient cotransport - coupled transport by a membrane protein